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Finding the Fourth Proportional to 206.17, 308.61 and 128.87

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Solution

The fourth proportional to 206.17, 308.61 and 128.87 is: 192.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.17 : 308.61 = 128.87 : x
  2. Step 2: Convert to fraction form
    206.17/308.61 = 128.87/x
  3. Step 3: Cross multiply
    206.17x = 308.61 × 128.87
  4. Step 4: Simplify right side
    206.17x = 39,769.32
  5. Step 5: Solve for x
    x = 39,769.32/206.17
  6. Step 6: Final answer
    x = 192.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.